Apparatus for transmitting sounds.



W. HARRISON. APPARATUS FOR TRANSMITTING SOUNDS.

APPLICATTON FILED MAR. 16, 1908.

1,150,267. Patented Aug. 17, 1915.

2 SHEETSSHEET l.

I avwento'z -w. HARRISON.

APPARATUS FOR TRANSMITTING souwos.

A PPLICATION FIL ED MAR. 16. I908. I

Patented Aug. 17, 1915.

2 SHEETS-SHEET 2L vweutoz said arc.

wan-row HARRISON, or BROOKLYN, New YORK APPARATUS FOR TRANSMITTING SOUNDS.

Specification 0t Letters Patent.

Patented Aug. 1?, 1915.

Application filed March 16, 1908. Serial No. 421,532.

To all whom it may concern:

Be itknown that I, WALTON HARRISON, a citizen of the. United States, residing in Brooklyn, in the county of Kings and State I of New York, have invented a certain new and useful Ap aratus for Transmitting Sounds, of whici the following is -a full, clear, and exact description.

My invention relates to the electrical transmission of sounds by aid of powerful currents suitable for Wireless telephony, and for wire telephones having multiple receiv -ers, loud speaking receivers, or receivers used for long distance transmission.

My invention contemplates the use of an are exposed to the direct action of sound waves, my special purpose being to increase the sensitiveness of the are by guiding the sound waves against, into and through certain definite portions thereof, and also against, into and through certain definite portions of the electrodes associated with My invention further embraces a provision for amplifying proportionately any current variations made by the action 'of sound wavesupon the arc, by causing the light from the arc, and particularly the ultra-violet rays of said light, to react upon the arc and quantitatively increase and diminish its resistance so as to'assist the direct action of the sound waves in controlling said resistance. While my invention is intended primarily for the transmission of articulate speech and other vocal sounds, and also instrumental music, it may be-used in a variety of other relations.

My invention is used in connection with a large variety of arcs, including the ordinary lighting arc, the flaming arc, the Simon speaking arc, lthe Duddel singing arc, and

the miscellaneous arcs used for the transmission of speech or other. vocal sounds,v either in wireless telephony or over lines.

In order that my invention may be readily understood I will first call attention toa few facts not generally knownconcerningthe nature and action of the electric) arc. As has been heretofore pointed out (see The Electric Arc, by Ayrton, page 393),"

the fundamental source of heat in the arc s not the positivecrater, butis a thin film of carbon vapor covering this crater, This film has a very high ohmic resistance as compared with other portions of the arc,-

and the vapor 'compri'singit is,'of course,

unconfined. In 1894, Trotter made the dis-.

covery (see The Electric Arc, ante page spot 18 a region of exceptional brilliancy,

and has an area of about one-fourth that of the crater. It is most noticeable, according to Trotter, in what he designated in the nomenclature of that day, as the humming are, though Ayrton expresses the belief that it is found in practically all other arcs. lhotometric and stroboscopic tests by Trotter showed that it had usually a definite shapewhich, however, was not always the same and was sometimes asymmetrical. These tests showed further that it had a rapid rotary movement, ranging from 100 to450 revolutions per second, and that its direction of rotation was sometimes reversed. Also (and here is a significant point) that the tone made by the arc in humming corresponded with the frequency of the revolutions of the bright spot, and

when these exceeded 450 per-second, the

,I have made the discovery that, if Trotters bright spot be disturbed or shaken by the aidof a force applied to it extraneously,

all other portions of the arc remaining as 'far as practicableundisturbed, the amperageof the entire current supporting the-arc is varied enormously, yet substantially in proportion to the disturbance of the bright spot. I have also discovered. that in the antipodal portion of the are, near the negative-electrode, there is another regionwhich behaves much like the bright spot, at least to the extent of controlling the current when disturbed, but in a lesser degree. More over, I have found it to be practicable,.by the use of a mouthpiece having at its bottom an opening of the order of a pinhole, to concentrate sound 'waves directly upon the bright spot, or upon its unnamed companion.

at the other end of the are, so as to impress upon the current variations greater in decovery that if the light, and especially the ultra-violet rays, emitted by the are be refiected back and focused upon the arc, variations in the condition of the latter are amplified or exaggerated so that corresponding variations, greater in degree, are made in the vention.

Reference is to be made to the accompanying drawings forming a part of this specification, and in which like letters indicate like parts. I 1

Figure 1 is a view partly in elevation and partly'diagrammatic, showing a circuit including a flaming arc, and means for directing sound waves through a minute opening toward the most sensitive part of the are for the purpose of varying the resistance of the arc, and thus controlling the line 'current' so as to transmit the sounds; this view also showing the are as surrounded by a spherical globe of glass, for reflecting the light of the arc and focusing the same for the purpose of affecting the current; Fig. 2 is a diagram showing my invention as applied to a singing are as used for wireless telephony, this are employing a solidmetallic negative electrode and a water-cooled metallic positive electrode, through the crater of which the sound waves reach the most sensitive portion of the arc; Fig. 3 is a detail of Fig. 2, showing how the mouthpiece extends into the water-cooled positive electrode andhas a minute opening which terminates flush with the positive crater of the arc; Fig. 4 is a view showing in section a pair of electrodes of a form-slightly difl erent from those shown in Fig. 2, the minute opening in this instance having its axis nearly tangential to the positive crater, and in line with a certain portion of the are selected because of its extreme sensitiveness, as hereinafter described; and Fig. 5 shows another pair of electrodes supporting an arc, the sound waves in this instance being directed into the arc through a minute opening in the negative electrode.

Mounted upon a support 1 of insulating material is a base 2 provided with a tubular holder 3, in which is a stem 4 adjustable by aid of a screw 5. The stem 4 carries a ring 6 provided with an adjusting screw, 7. A mouthpiece 8 is provided with a rear wall 9 having a minute opening 10, preferably about of an inch in diameter.

Extending upwardly from a base 11 is a stem 12, supporting brackets 13, 14, insu' lated therefro'mby aid of sleeves 15, 1-6,of

non-conducting material. Adjusting screws 17, 18am used for raising'and lowering the in suitable position, and permit their ad justment from time to time. An are 31 is formed between the electrodes, the upper end of the are springing from the crater 32 of the positive carbon, and the lower end of the arc resting upon the tip of the negative carbon. The portion of the are designated by Ayrton and Trotter as the bright spot is indicated by an appropriate legend. This bright spot is the most sensitive portion of the are, for purposes of controlling the current by the acoustical action of sound waves. At 34 is a glass globe supported upon the mouthpiece 8 and rovided with ventilation holes 35; This glo e is not essential for all purposes, and may be discarded whenever receivers may be substituted. Sounds of any kind, including articulate speech, being made in the mouthpiece, the sound waves pass through the opening 10 and cause the bright spot to vibrate. .-This varies the resistance of the arc, and impressesupon the currentcharacteristics analogous to soundwaves, thus reproducing the sounds by aid of the receivers. The current variations are amplified by the action of the ultra-violet light, as above described.

; desired. Its purposeis to reflect the light, "and especially the ultra-violet rays, back The chemical and physical composition of the bright spot, its temperature, and its exact chemical and physical relations to the film of vapor in immediate contact with the positive crater, as well as the cause of its sensitiveness, are subjects upon which volumes of speculative literature could be written. and action of my invention, however, there appears to be no necessity for pursuing this phase of the subject. Sufiice it to say, in general terms, that the arc has an exceptionally sensitive region easily located by reference to the bright spot, but which may In order to explain the construction.

be located also by reference to the positive readily accessible from the outside; that it approximates the hottest portion, and that by concentrating the sound waves into the form of a column of very small diameter, they can be directed into this region. The shape of the positive crater and of the elec trodes may assist this object. In practice, I simply direct the sound waves into the proximate center of the positive crater and thus into the hottest portion of the arc. The globe 34 increases the variations'of the current,.no matter how they are initially produced. This action is due to the fact that varying quantities of the light rays, and especially the ultra-violet rays, when sent by reflection and diffraction back into the arc, vary its state of ionization. Suppose, for

. instance, that a particular sound wave or a function thereof by its direct acoustical action causes a momentary increase in the current. The light becomes momentarily brighter, the number of rays emitted from and then concentrated upon the arc is correspondingly increased, and the ionic activity of the arc is enhanced, thereby decreasing its resistance and further increasing the current. When, however, the direct acoustical action happens to diminish the current, it also diminishes the number of rays and lessens the ionic activity, thereby increasing the resistanceof the around, consequently cutting down the current. As ordinary glass is opaque to ultra-violet rays, it answers very well as a material for the globe, which need not necessarily be made opaque to ordinary light.

Inthe arrangement shown in Fig. 2, two choking coils 42, 43 are connected with direct current mains 44, 45, and from the choking coil 42 a wire 46 leads to a copper cylinder 47, filled with water 48, and supporting a globe 49 of glass opaque to ultra-violet rays. A mouthpiece 50 has a pinhole opening 51, preferably about of an inch in diameter, immediately over the bright spot,

and in close proximity thereto. This opening is in axial alinement with the bright spot, so as to readily direct sound waves into, through and against the same. The water-cooled cylinder is the positive elec-' trode. The negative electrode 52 is a solid metallic rod, having its; upper; end hemispherical; It, is connected by a wire 53 with the choking coil 43. Awire 54 leads from the positive electrode to a condenser 55, which is connected by a wire 56 with the primary winding 57 which is connected by -a wire. 58jwith the negative electrode 52,

and is in inductive relation with a secondary winding 5;), the latter being directly connected with an aerial 60 and grounded at 61.

The capacity of the condenser 55 and, the

&

waves are concentrated and pass through.

the pinhole opening and into the sensitive region of the arc, agitating the bright spot and the-portions of the are in immediate proximity thereto. In doing this the sound waves also pass directly into the hottest part of the positive crater and through the thin film of vapor in immediate contact with said crater. Moreover, it is throughithe center of this-film that the sound waves pass when they are directed into the geometrical axis of the are, as indicated in Figs. 2, 3, 4 and 5. The sound waves thus disturb the film and the center of the light spot, and furthermore, have more or less tendency to disturb the temperature of the crater. All of these effects contribute to a common end, to 'wit, the variation of the resistance of the arc in accordance with sound waves. This much being granted, the rest of the action is substantiallythe same as already known and heretofore employed for purposes of wireless telephony.

In Fig. 4 the water-cooled cylinder is shown'at 63, the mouthpiece at 64, and the pinhole opening at 65. In this device the at 66, the water for cooling the same at 67,

and the copper bottom for the cylinder at 68. This copper bottom is provided with a protuberance 69, for centering the arc and steadying the bright spot. The mouthpiece is shown at 70, and is made of copper having an integral upturned portion 50, which is made comparatively thick in order to withstand the heat, and is provided with a pinhole opening '71 which is directed toward the bright spot, and is in axial alinement with the center thereof. As the arc in a. device of this kind can. be made very short,

the pinhole opening is brought into close proximity to the bright spot, the center of the film and the center of the positive 'crater, although in this instance, as in the othcrs,-the upper electrode is positive and the lower one negative. The glass globe,

, ing the air or other free medium whereby being removable, can be used'in connection with any of the arcs above described, or discarded whenever desired.

I make no attempt to illustrate the film of vapor intermediate the bright spot and the positive crater.

The gases and vapors comprising the body of the, are together constitute a transient conductor which, being heated by the passage of electricity through it, is in a state of intense ionic activity as is also the air to which the arc is exposed. My apparatus, therefore, acting in conjunction with sound waves, makes alterations in the state of ionization of both the. transient conductor and the air, therebyafi'ecting the resistance of the transient conductor. What is true of the arc is in general true of any other transient conductor which, when heated by the passage of electricity through it, becomes ionized or has the effect of ionizit is surrounded.

I use the expression transient conductor in a broad sense, meanin thereby to include a gas, a vapor, or a mix ure of gases ters Patent:

and vapors, capable of serving temporarily as a conductor when heated, or otherwise directly acted upon, by electricity. I also use the term aeriform body in a broadsense, meaning to include thereby any gas,

vapor or other practically weightless body jj'f of air-like form, whether free, confined, or

partially confined.

Having thus described my invention, I claim as new and desire to secure by Let- 1. The combination of a circuit including an electric discharge crossinga' gap and having within said gap a portion particularly sensitive to ionization, and means for selectively subjecting said portionto the action of a varying ionizing force.

2. The combination of a circuit including an electric discharge having a predetermined portion particularly sensitive to ionization, and means for selectively applying to said sensitive portion an ionizing force havin variations analogousto sound waves.

waves, one of said electrodes being provided with means for cooling it in order to in- Goples of this patent may be ontaiiml for cooling both said electrode and said portion.

of said mouthpiece.

6. The combination of a circuit including an arc, a mouthpiece provided with a portion extending into close proximity to said are for the purpose of subjecting said are to resistance variations analogous to sound waves, and cooling mechanism connected with said portion of said mouthpiece for the purpose of cooling the same.

I 7. Thecombination of a circuit including an arc, a telephonic receiver controllable by said circuit, mechanism including a. mouthpiece directed toward said are for exposing the latter to sound waves, and means for cooling a portion of said mouthpiece in close proximity to said arc.

-8. The combination of a circuit including an arc provided-with a particularly sensitive portion having a high temperature, a mouthpiece having a portion extending close to :said sensitive portion of said are, and hav- =ing a minute opening ad acent'to saidsensitive portion of saidarc, and means for preventing undue heating of said portion of said mouthpiece.

9. The combination of a circuit including a gap across which electricity flows, said gap with said electricity flowing across it having a portion particularly sensitive to disturbances extraneous to said circuit, and means extraneous to said circuit and acting conjointly with sound waves iorselectively disturbing said portion. a

10. The combination of a circuit including a gap across which electricity flows, said-circuit being sensitive to ultra-violet light thrown into said gap, and means for directing into said gap' sound-controlled- 'quanti ties of ultra-violet light.

11. The combination of a circuit including a gap acrosswhich electricity flows, said circuit being sensitive to ultra-violet light, and means for exposing said gap to variations, analogous to sound waves, in the quantity of ultra-violet light thrown thereupon.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

WALTON HARRISON. Witnesses F. D. AMMEN, W. W. Hon'r.

five'cen'cs each, b addressing the Gommissioner of Patents,

Washington, 2010. 

